Originally Posted by turnbull
Well it is not so much a fact of "less is more" in the case of backspacing. This may not be 100% accurate, but it close enough to give you an idea of what backspacing means: backspacing is a measurement from where the wheel is mounted on the axle to the edge of the wheel on the inner side. In actuality, 15x8 wheels would cause your tires to stick out more than 15x7 wheels, IF they have the same backspacing. Here is an example to see how this works: let's say they both have 4" backspacing. That means both wheels go 4" inward from where they are mounted. However, this leaves 4" left unaccounted for on the 15x8 and 3" left unaccounted on the 15X7. That means that the 15x8 will stick out 4" from where the wheel is mounted, and the 15x7 will stick out 3" from where the wheel is mounted. In other words, the center of the 15x8 actually 0.5" farther "out" than the 15x7.
From what I've read and heard, this is exactly correct.
Depending on what factory wheels your jeep as now, your back spacing is either 5", 5.5" or 5.25" if you have the "Gambler" wheels. (someone please correct me if I'm wrong) For example, I have the "Ravine" wheels on my 06 which have 5.5 backspacing and I'm playing on getting the pro comp series 51 15x8 with the 3.75 back spacing so once I get them, they will stick out 1.75" further than they do now.
Keep in mind, that scenario doesn't account for wider tires, only a smaller amount of back spacing for the wheels.